What is the hydroxide ion concentration in mol/L of a solution if 0.080 grams of NaOH are dissolved in 2.0 liters of solution?
moles NaOH = grams/molar mass.
M = moles/2L
To find the hydroxide ion concentration in mol/L (or molarity), we need to first convert the given mass of NaOH to moles, and then divide it by the volume of the solution.
Step 1: Convert the mass of NaOH to moles
The molar mass of NaOH (sodium hydroxide) can be found by adding the atomic masses of its constituent elements, Na (sodium), O (oxygen), and H (hydrogen). The atomic masses are:
- Sodium (Na): 22.99 g/mol
- Oxygen (O): 16.00 g/mol
- Hydrogen (H): 1.01 g/mol
So, the molar mass of NaOH is:
22.99 g/mol (Na) + 16.00 g/mol (O) + 1.01 g/mol (H) = 40.00 g/mol
Now, divide the given mass of NaOH by its molar mass to obtain the number of moles:
0.080 g / 40.00 g/mol = 0.002 mol
Step 2: Calculate the hydroxide ion concentration in mol/L
Divide the number of moles of NaOH by the volume of the solution expressed in liters:
0.002 mol / 2.0 L = 0.001 mol/L
Therefore, the hydroxide ion concentration in mol/L of the solution is 0.001 mol/L.